NONLINEAR SEISMIC ANALYSIS OF SKEWED BRIDGES WITH DIFFERENT GEOMETRY CONFIGURATIONS

Abstract

Response of bridges during seismic events is an important subject; particularly, the skewed bridges that are sometimes used in certain situations such as in highways to achieve the required mobility between two intersecting highways or to solve any other traffic flow issues. However, such skewed bridges have a complex response towards earthquake events due to their unconventional structural geometry. This study is focusing on the skew effect on the seismic behavior of single and multiple span bridges under different cases of substructure/superstructure connections considering soil-abutment-interaction.

This study attempts to investigate the skew effect through bridges with single and multiple spans and with different skew angles (varying from 0˚ to 60˚) under seven different ground motions. The analyses are conducted using the open source software platform OpenSees; while for relatively large models OpenSeesSP for parallel computation was used and aided by OpenSees Navigator to facilitate modeling procedure.

Results indicate that seismic demand generally increases with the increase of skew angle; particularly for skew angle larger than 30˚. It is found that the skew effect for skew angle larger than 30˚ is predominant whether the deck is rigidly connected with piers or is rested on bearings nevertheless some geometry configurations resulted in reduction in skew effect, as well as enhancement in seismic response.